"I don’t believe he [O’Grady] wanted to batter and beat him," Linn said. "He may have wanted to give him a piece of his mind."

Mendoza said he pulled up his Route 62 Archer Line bus to the stop at State and Monroe on Sept. 12, 2009. Surveillance video on board the bus shows the officer, reportedly angry after the bike he was riding was almost struck by the bus, board the bus and approach Mendoza, but it doesn't show any contact between the driver and the cop.

The suit claimed O'Grady "savagely" beat and punched Mendoza.

Chicago police didn't buy Mendoza's story, and they alleged he lied about the attack and the nature of his injuries.

Mendoza initially told investigators that O’Grady also poked him in the eye. But later, Mendoza told authorities he was punched in the face, head and shoulders and had lost consciousness, prosecutors said.